JPH0582009A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize simplification of the structure by simplification of the insulation between the current transformer and the corresponding charging part, and improvement of assembly workability. [Structure] When the base 1a constituting the mold case 1 is integrally molded, a concave fitting portion 11 having a shape that sandwiches the movable contact arm 4 from both sides is provided on the outer surface of the base 1a by recessing the same inward. The current transformer 12 for detecting the overload current is provided with a U-shaped iron core 13 having a gap, and the movable contact arm 4 is positioned in the gap with respect to the concave fitting portion 11. Arranged in a state. As a result, the current transformer 12 outputs a detection voltage indicating the magnitude of the load current flowing through the movable contact arm 4 serving as the primary conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker in which a main contact interposed in a load power feeding path is opened in response to an overload current.

[0002]

2. Description of the Related Art As an example of this type of circuit breaker, conventionally, a current transformer in which a conductor forming a load power feeding path is penetrated in a molded case made of an insulating material, and a current transformer A control circuit that outputs an overcurrent trip signal based on the magnitude of the detected load current value, and a trip device that trips the main contact interposed in the load power supply path when the overcurrent trip signal is output. It is provided with a structure that is opened by.

[0003]

In the above structure, a relatively troublesome work of penetrating the current transformer into the current transformer is required at the time of assembly, which deteriorates the assembly workability. There is. Further, there is a problem that the structure for the insulation is complicated because it is necessary to sufficiently insulate between the conductor that is the charging portion and the current transformer that penetrates the conductor.

The present invention has been made in view of the above circumstances, and an object thereof is to simplify the insulation between the current transformer and the corresponding charging portion without impairing the function of the current transformer. (EN) A circuit breaker capable of simplifying the structure and improving the assembling workability.

[0005]

In order to achieve the above object, the present invention provides a load feeding path including a main contact, a current transformer for detecting a load current, and a detection output of the current transformer in a molded case. A control circuit that outputs an overcurrent trip signal based on
In a circuit breaker containing a trip device that receives the overcurrent trip signal and opens a main contact provided in a load power supply path, the current transformer is configured to have a gap between iron cores. By providing a concave fitting portion having a shape sandwiching the molding case on the outer surface of the molding case by inwardly forming the molding case, and disposing the current transformer in the concave fitting portion. It is configured such that the conductor portion is located in the gap of the current transformer.

[0006]

[Function] Since the conductor portion forming the load power feeding path is located in the gap of the current transformer, if a fault current such as an overload current flows in the load power feeding path, the current transformer will cause the fault. The detection signal corresponding to the current is output. Then, the control circuit outputs an overcurrent trip signal based on the detection output of the current transformer, and the trip device that receives this signal opens the main contact in the load power feeding path. Trigger operation.

In this case, since the current transformer only needs to be arranged in the recessed fitting portion provided on the outer surface of the mold case, the assembling workability is improved, and the current transformer and the load power feeding path are improved. Since the mold case is interposed between the conductor part and the conductor part, the insulation between them is performed by the mold case, so that the structure for insulating the current transformer can be simplified. become.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a three-phase earth leakage breaker will be described below with reference to the drawings.

In FIG. 1, a mold case 1 for insulation is used.
The base 1a and the cover 1b constituting the above are integrally formed of plastic, and the base 1a is provided with the power source side terminal 2 having the conductor portion 2a forming the load power feeding path and the conductor portion 3a also forming the load power feeding path. The load side terminals 3 are provided for every three phases.

A movable contact arm 4 as a conductor portion provided for three phases is rotatably supported by a crossbar 5 via a connecting pin 6, and the conductor portion of the power source side terminal 2 is provided at the tip thereof. There is provided a movable contact 8 which comes into contact with and separates from a fixed contact 7 fixed to 2a. Further, the base end portion of the movable contact arm 4 is connected to the conductor portion 3a of the load side terminal 3 via the flexible conductor 4a.

Here, the fixed contact 7 and the movable contact 8 constitute a main contact 9. Therefore, the main contact 9 is interposed in the load power feeding path constituted by the conductor portions 2a, 3a. Then, the load feeding path is opened / closed in accordance with the rotation of the movable contact arm 4.

The crossbar 5 forms a part of an opening / closing mechanism (not shown) arranged in the center of the mold case 1. The opening / closing mechanism is operated according to the operation of the handle 10 projecting outside the cover 1b. The movable contact arm 4 is rotated by a known structure.

When the base 1a constituting the mold case 1 is integrally molded, the movable contact arms 4 for the three phases are formed by recessing the outer surface (lower surface) of the base 1a inward (upward). Three concave fitting portions 11 (only one is shown) having a shape sandwiched from both sides are provided.

In the current transformer 12 provided for three phases, as shown in FIG. 2, the secondary winding 14 is wound around the leg portion of the "U" -shaped iron core 13 having the gap 13a. Bobbin 1
5, the movable contact arm 4 is arranged in the gap 13a with respect to the recessed fitting portion 11. As a result, the current transformer 12 outputs a detection voltage at a level according to the magnitude of the load current flowing through the movable contact arm 4 serving as the primary conductor.

Auxiliary current transformer 16 also provided for three phases
Is disposed in an empty space between the switching mechanism (not shown) and the power supply side terminal 2, and is configured to generate an output according to a load current flowing in each phase load power supply path. Specifically, as shown in FIG. 3, the auxiliary current transformer 16 has a bobbin 19 in which a secondary winding 18 is wound around the leg portion of a rectangular core 17 of a gapless type. The power supply side terminal 2 is provided with respect to the conductor penetrating opening 20 formed in the iron core 17.
The conductor portion 2a is disposed so as to penetrate therethrough. As a result, the auxiliary current transformer 16 outputs a detection voltage at a level according to the magnitude of the load current flowing through the conductor portion 2a serving as the primary conductor.

The zero-phase current transformer 21 is arranged in an empty space between the switch mechanism (not shown) and the load side terminal 3,
It is configured to detect a ground fault current flowing in the load power supply path. The zero-phase current transformer 21 has a shape similar to that of the auxiliary current transformer 16, and the conductor portion 3 of the load side terminal 3 is provided.
It is arranged so that a for three phases is collectively used as a primary conductor.
As a result, the zero-phase current transformer 21 outputs a detection voltage at a level according to the magnitude of the ground fault current flowing through the conductor portions 3a for the three phases, which are primary conductors.

In the empty space between the opening / closing mechanism in which the zero-phase current transformer 21 is arranged and the load-side terminal 3, a control circuit 22 and a movable contact arm 4 which will be described later are arranged to rotate in the opening direction. A removal device 23 is arranged.

Therefore, the outline of the electrical configuration will be described below with reference to FIG.

In FIG. 4, the trip device 23 is
The trip coil 23a is provided, and when the trip coil 23a is energized, the movable contact arm 4 is rotated in an opening direction through an opening / closing mechanism (not shown), thereby opening the main contact 9.

The control circuit 22 has the following structure. That is, the first rectifier circuit 24 rectifies the detected voltage from the current transformer 12 for each phase, and supplies the rectified output to the resistor 25 that constitutes the burden circuit. As a result, the resistance 25
A voltage signal Vf having a level corresponding to the magnitude of the load current is output from both ends of the. The second rectifier circuit 26 rectifies the detected voltage from the auxiliary current transformer 16 for each phase and supplies the rectified output to the power supply circuit 27. The auxiliary power supply circuit 28 is configured to rectify the output from between the two phases of the load side terminal 3.

The overcurrent trip circuit 29 fed from the power supply circuit 27 operates when the load current level indicated by the voltage signal Vf from the resistor 25 is equal to or higher than a predetermined time limit operation level for a set operation time or longer. , And outputs an overcurrent trip signal Sa. When the overcurrent trip signal Sa is output, the thyristor 30
Turns on, and accordingly trip coil 23 is turned on.
The second rectifier circuit 26 and the auxiliary power supply circuit 28 for a
Is configured to be energized via the diodes 26a and 28a.

The earth leakage trip circuit 31 fed from the auxiliary power supply circuit 28 has a sensitivity current level in which the level of the ground fault current indicated by the detection voltage output from the secondary side of the zero-phase current transformer 21 is preset. When it becomes the above, it has become the composition which outputs earth leakage trip signal Sb. When the earth leakage trip signal Sb is output in this manner, the thyristor 32 is turned on, and in response to this, the trip coil 23a is supplied from the second rectifier circuit 26 and the auxiliary power supply circuit 28 via the diodes 26a and 28a. It is configured to be energized.

According to the above structure, the conductors 2a, 3a,
When a fault current such as an overload current or a short circuit current flows through the load conducting path formed by the movable contact arm 4, the fault current is detected by the current transformer 12, and the level of the detected current is When the state of being above the predetermined time limit operation level continues for the set operation time or longer, the overcurrent trip circuit 29 outputs the overcurrent trip signal Sa. Then, since the trip coil 23a is energized by turning on the thyristor 30, an overcurrent trip operation is performed in which the main contact 9 is opened due to a fault current.

When a ground fault current flows in the load energizing path,
The ground fault current is detected by the zero-phase current transformer 21, and the leakage trip circuit 31 outputs the leakage trip signal Sb when the level of the detected current is equal to or higher than the sensitivity current level. Then, the trip coil 23a is energized by the turn-on of the thyristor 32, so that the earth leakage current opens the main contact 9 to perform the earth leakage trip operation.

However, according to the present embodiment described above, the current transformer 12 only needs to be arranged in the concave fitting portion 11 provided on the outer surface of the base 1a of the mold case 1, so that the assembling workability thereof is improved. It will be improved and this current transformer 12
Since the base 1a made of an insulating material is interposed between the movable contact arm 4 and the movable contact arm 4 which is the charging portion, the insulation between them is performed by the base 1a. Will be able to simplify the structure for.

Further, according to the present embodiment, a portion different from the arrangement portion of the zero-phase current transformer 16 which requires a relatively large space (that is, an empty space between the opening / closing mechanism and the load side terminal 3 not shown). (That is, the open space between the opening / closing mechanism and the power supply side terminal 2) and the current transformer 12 and the auxiliary current transformer 16
Since the structure is provided, the dead space existing between the opening / closing mechanism and the power supply side terminal 2 can be effectively used, and the space required between the opening / closing mechanism and the load side terminal 3 can be reduced, and the overall size of the device can be reduced. Will be realized.

In the above embodiment, the auxiliary current transformer 16 is arranged in the empty space between the switching mechanism and the power supply side terminal 2, but this is arranged in the empty space between the switching mechanism and the load side terminal 3. In this case, since the auxiliary current transformer 16 is dedicated to the power source and has a relatively small size, there is no fear of hindering the overall size reduction.

[0028]

As described above, according to the present invention, the current transformer is formed in the shape having the gap between the iron cores, and the mold case is formed inward on the outer surface of the mold case. A concave fitting portion having a shape sandwiching the conductor portion forming the load power supply path from both sides is provided, and by disposing the current transformer in the concave fitting portion, the conductor portion is positioned in the gap of the current transformer. Since it is configured, the insulation between the current transformer and the corresponding charging part can be simplified without impairing the load current detection function of the current transformer, and the structure can be simplified, and the assembly workability is also improved. It has an excellent effect that the improvement of

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

2] Front view of current transformer

FIG. 3 is a front view of an auxiliary current transformer.

FIG. 4 is a connection diagram schematically showing an electrical configuration.

[Explanation of symbols]

In the figure, 1 is a molded case, 1a is a base, 1b is a cover, 2 is a power source side terminal, 2a is a conductor portion (load feeding path), 3
Is a load side terminal, 3a is a conductor portion (load feeding path), 4 is a movable contact arm (conductor portion), 7 is a fixed contact,
8 is a movable contact, 9 is a main contact, 11 is a concave fitting portion, 12
Is a current transformer, 13a is a gap, 16 is an auxiliary current transformer, 21
Is a zero-phase current transformer, 22 is a control circuit, 23 is a trip device,
27 is a power supply circuit, 28 is an auxiliary power supply circuit, 29 is an overcurrent trip circuit, and 31 is an earth leakage trip circuit.

Claims (1)

[Claims] 1. A load feeding path including a main contact, a current transformer for detecting a load current flowing through the load feeding path in a molded case, and an overcurrent drawing based on a detection output of the current transformer. A circuit breaker comprising a control circuit that outputs a disconnection signal and a tripping device that receives the overcurrent tripping signal and opens the main contact, wherein the current transformer has a gap between iron cores. In addition to being configured in a shape, a concave fitting portion having a shape sandwiching the conductor portion constituting the load power supply path from both sides is provided on the outer surface of the molding case by forming the molding case inwardly. A circuit breaker, characterized in that the conductor portion is arranged in a gap of the current transformer by disposing the current transformer.